Transformer with tubular conductor coil

ABSTRACT

A transformer capable of resisting, without deformation, strong short circuit currents. The current transformer is immersed in an insulating liquid inside a container. Its primary winding consists of a tubular coil which is cooled by the circulation of insulating liquid, such as a suitable oil, through the tubular coil. An elongated tubular portion of the coil is separated into inlet and outlet channels for the cooling oil by an elongated flat conductor positioned within the tubular portion and insulated therefrom.

United States Patent Inventor Jenn Trabut Aix-Les-Bnlns, France Appl. No. 16,444 Filed Mar. 4, 1970 Patented Oct. 5, 1971 Assignee Alsthom'Savoisienne Saint-Onen, France Priority Mar. 7, 1969 France 6906347 TRANSFORMER WITH TUBULAR CONDUCTOR COIL '3} 4 Claims, 3 Drawing Figs.

us. or 336/62 rm. Cl non 27/08 Field 6: Search 336/55, 62,

[56] References Cited UNITED STATES PATENTS 2,075,380 3/1937 Varian 336/62 X 2,841,679 7/1958 Yamazaki 219/1051 3,299,383 1/1967 Conner et al. 336/62 X FOREIGN PATENTS 1,002,388 8/1965 Great Britain 336/62 Primary Examiner-Thomas J. Kozma Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: A transformer capable of resisting, without deformation, strong short circuit currents. The current tr'ansformer is immersed in an insulating liquid inside a container.

Its primary winding consists of a tubular coil which is cooled by the circulation of insulating liquid, such as a suitable oil, through the tubular coil. An elongated tubular portion of the coil is separated into inlet and outlet channels for the cooling oil by an elongated flat conductor positioned within the tubular portion and insulated therefrom.

TRANSFORMER WITH TUBULAR CONDUCTOR COIL BACKGROUND OF THE INVENTION The present invention relates to a high-tension strong-current transformer immersed in an insulating liquid inside a container and, more particularly, to such a transformer having a new and improved primary winding construction.

The forming of a primary winding of such a transformer by a tubular conductor coil in which the insulating liquid can circulate is already known. According to a known arrangement, the current lead-in wires consist of two coaxial conducting tubes so that the inside of the central tube and the space between the two tubes act as a canal for supplying and evacuating the cooling liquid circulating by thermosiphon action in the tubular coil of the primary winding. However, the connection of the two coaxial tubes at the ends of the tubular conducting coil requires costly machining. The present invention overcomes this disadvantage.

SUMMARY OF THE INVENTION The transformer of the present invention comprises a primary winding in the form of a tubular conducting coil which forms a turn galvanically interrupted by an insulating sleeve. One of the ends of the coil is electrically connected to a rectilinear tubular conductor, and the other end is electrically connected to a flat conductor which is kept in place inside the rectilinear tubular conductor by insulating elements, so as to divide the inside of this tubular conductor into two enclosures through which the insulating liquid is brought into the tubular coil and is evacuated from the latter into the receptacle of the transformer.

The use of such a flat conductor in the present invention is less costly than the use of the central tubular conductor in the two coaxial tube constructions of the prior art and it is easier to make connections at the terminals of the device.

According to a preferred embodiment, the insulating elements which keep the flat conductor in position are bars which extend all along the rectilinear tubular conductor, each having a groove in which an edge of the flat conductor is mounted.

According to another preferred embodiment, the said rectilinear tubular conductor is cut at its upper part along half of its cross section so that the two enclosures, separated inside the tube by the flat conductor, open out into the receptacle at different levels at which the density of the liquids is different.

According to a further preferred embodiment, the said flat conductor consists of several conductors transposed in relation to one another along their length, to reduce the skin effect.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of an elevation of a primary winding according to the invention. I

FIG. 2 is a plan view of the primary winding shown in FIG. 1.

FIG. 3 is a side elevational view of the flat conductor formed of several conductors grouped together in parallel in a transposed bundle.

DESCRIPTION OF THE PREFERRED EMBODIMENT The current transformer is immersed in an insulating liquid 10 inside a container 11. The primary winding shown in FIGS. 1 and 2 comprises a single turn consisting of a tubular conductor coil 1 which is interrupted at 2 by an insulating sleeve, and is soldered or otherwise connected at 10 to the inner end of the flat conductor 4.

The current lead-in wires consist, on the one hand, of a tubular conductor 3, and, on the other, of the elongated flat conductor 4, isolated from the tube 3 by a pair of elongated insulating bars 5 which each have a groove in which an edge of the flat conductor is mounted.

The flat conductor 4 IS arranged so as to dlvlde the inside of the tube 3 into two enclosures 6 and 7 in which cooling oil can circulate. The tube 3 is cut at its upper end along half its cross section, on part of its length so that the interior enclosure 6 opens out at 8 at a level lower than the interior enclosure 7 which opens at 9. The density of the oil in the receptacle is higher at the level of opening 8 than at the level of opening 9. The circulation of the oil in the enclosures 6 and 7, as well as in the tubular coil 1, is thus effected by thennosiphon action in the direction of the arrows.

The flat conductor 4 can consist of a single conductor having a rectangular cross section as shown in FIG. 2. However, as has been said above, the conductor 4 can, to great advantage, consist of several insulated conductors 4a grouped together, in parallel, in a transposed bundle to reduce the skin effect, as shown in FIG. 3.

What is claimed is:

1. In a current transformer, immersed in an insulating liquid inside a receptacle, whose primary winding consists of a tubular conducting coil, the improvement wherein the tubular coil forms a turn which is galvanically interrupted by an insulating sleeve, one end of said turn being electrically connected to a rectilinear tubular conductor, and the other end of said turn being electrically connected to a substantially flat conductor which is mounted inside the rectilinear tubular conductor by means of insulating elements so as to divide the inside of the said rectilinear conductor into two enclosures through which the insulating liquid is brought into the tubular coil and is evacuated from it into the receptacle of the transformer.

2. A current transformer according to claim 1, wherein the insulating elements which keep the flat conductor in place are bars which extend all along the length of the rectilinear tubular conductor and each has a groove in which an edge of the flat conductor is mounted.

3. A current transformer according to claim 1, wherein the rectilinear tubular conductor is cut at its upper end along half of its cross section so that the two enclosures separated inside the tube by the flat conductor open out into the receptacle at different levels where the density of the insulating liquids is different.

4. A current transformer according to claim I, wherein the said flat conductor comprises a plurality of insulated conductors grouped in parallel in a bundle, where the said conductors are transposed along their length so as to reduce the skin effect. 

1. In a current transformer, immersed in an insulating liquid inside a receptacle, whose primary winding consists of a tubular conducting coil, the improvement wherein the tubular coil forms a turn which is galvanically interrupted by an insulating sleeve, one end of said turn being electrically connected to a rectilinear tubular conductor, and the other end of said turn being electrically connected to a substantially flat conductor which is mounted inside the rectilinear tubular conductor by means of insulating elements so as to divide the inside of the said rectilinear conductor into two enclosures through which the insulating liquid is brought into the tubular coil and is evacuated from it into the receptacle of the transformer.
 2. A current transformer according to claim 1, wherein the insulating elements which keep the flat conductor in place are bars which extend all along the length of the rectilinear tubular conductor and each has a groove in which an edge of the flat conductor is mounted.
 3. A current transformer according to claim 1, wherein the rectilinear tubular conductor is cut at its upper end along half of its cross section so that the two enclosures separated inside the tube by the flat conductor open out into the receptacle at different levels where the density of the insulating liquids is different.
 4. A current transformer according to claim 1, wherein the said flat conductor comprises a plurality of insulated conductors grouped in parallel in a bundle, where the said conductors are transposed along their length so as to reduce the skin effect. 